Advances in minimally invasive surgical procedures and the development of novel surgical instruments have enabled surgeons to access delicate areas of the body that were previously off-limits or only accessible through highly invasive procedures. These innovations have undoubtedly resulted in significant improvements in treatment options and patient outcomes for a variety of maladies. As the complexity of surgical procedures and the number of tools to diagnose and treat the underlying condition expand, surgeons are confronted with a variety of options. For example, retinal surgical procedures (which typically rely on a variety of instruments, including an illuminating light source, a treatment laser, a vitrector, an aspirator, etc.) are performed via ports or cannulated incisions in the eye, limiting the number of instruments that can be introduced into the eye simultaneously. Likewise, orthopedic procedures (e.g., knee reconstruction) typically involve a variety of instruments and tools, of which only a limited number can be inserted into the patient for access to the surgical site at any particular moment. The need to constantly swap out instruments because of limited access to the surgical site is frequently a problematic and time-consuming distraction to the surgeon.
In addition, new diagnostic techniques—including new or improved imaging modalities—provide surgeons with more information and a better understanding of the area being treated. This enables surgeon to collect, for example, real-time and non-destructive biopsies including analysis of regions that are typically difficult to access. These innovations have resulted in significant improvements in treatment options and patient outcomes for a variety of maladies. One such useful diagnostic technique is optical coherence tomography (OCT), an interferometric technique for noninvasive diagnosis and imaging utilizing (typically infrared) light. A particular mode of OCT, termed “A-scan,” provides one-dimensional axial depth scans of the tissue of interest, thus providing information on the identity, size, and depth of subsurface features. A series of spatially adjacent A-scans (typically lying in a straight line) may be combined to form a two-dimensional reconstructed image of the imaged area (termed a “B-scan”), offering surgeons a visual reconstruction of subsurface features. Likewise, three-dimensional images, termed “C-scans,” may be formed by “stacking” multiple B-scans.
While the capabilities of medical and veterinary devices continue to improve, their use is often complicated or prevented in many procedures because the motion and placement of such devices cannot be accurately and quickly determined. Consequently, there is a continuing need for systems and methods of measuring and tracking the motion and placement of such devices during surgical procedures, enabling their use in a broader range of procedures, and making the procedures faster and more accurate.